Monday may have been Earth’s warmest day on record. Then came Tuesday and Wednesday

A person’s profile against the sun
A visitor to Signal Hill seeks respite from hotter temperatures inland. Preliminary data show Monday, Tuesday and Wednesday were the hottest days on record in terms of global average temperature.
(Luis Sinco / Los Angeles Times)
Share via

Californians sweltering under the first heat wave of the season — you’re not alone.

Researchers this week announced that Monday might have been the hottest day recorded on Earth, and then that record was unofficially broken on Tuesday and temperatures remained high on Wednesday.

Although scientists still need to verify global average temperature figures to officially cement this week’s sweltering milestones, experts say the data reflect the continued effects of climate change, and may not be the last records set this year given the return of El Niño.

The global average daily temperature Monday was 62.6 degrees — the highest since modern record-keeping began more than four decades ago, according to the University of Maine’s Climate Reanalyzer project. The average temperature Tuesday was higher still, at 62.9 degrees. The recorded temperature remained the same for Wednesday, data show.


The previous record captured by the project, 62.46 degrees, was set in 2016.

There is an 84% chance the system will be of moderate strength, and a 56% chance it will become a strong event at its peak, forecasters said.

June 9, 2023

Monday’s record was “driven by the combination of El Niño on top of global warming,” according to Robert Rohde, lead scientist with Berkeley Earth, an environmental data science nonprofit.

“We may well see a few even warmer days over the next six weeks,” he wrote on Twitter.

Climate Reanalyzer data come from a National Oceanic and Atmospheric Administration computer simulation that pulls information from satellite imagery used for weather forecasts.

In a statement issued Thursday, the National Centers for Environmental Prediction/National Weather Service, under NOAA, said the agency would not confirm the findings made by the University of Maine scientists about the global temperatures recorded on Monday and Tuesday. The agency does not track and validate global daily record temperatures, but only on a monthly and annual basis.

“The University of Maine’s Climate Reanalyzer used model output data from NOAA’s National Centers for Environmental Prediction (NCEP), not actual temperature measurements. These model data are not suitable to be used as a proxy for actual surface temperatures and climate records,” the statement said.

“Although NOAA cannot validate the methodology or conclusion of the University of Maine analysis, we recognize that we are in a warm period due to climate change, and combined with El Niño and hot summer conditions, we’re seeing record warm surface temperatures being recorded at many locations across the globe.”


Southern Californians should brace for another few days of high temperatures, as the first heat wave of the summer continues to bear down on the region.

July 3, 2023

Rohde noted that data from the Climate Reanalyzer only go back to 1979. But, he added, “other data sets let us look further back and conclude that this day was warmer than any point since instrumental measurements began, and probably for a long time before that as well.”

“Global warming is leading us into an unfamiliar world,” he said.

The European Union’s Copernicus Climate Change Service, which uses a different model for temperature analysis, announced that its preliminary data for Monday were also record-breaking.

Although an average of 62.9 degrees doesn’t sound particularly warm, researchers point out some parts of the globe are in the middle of winter. Antarctic sea ice at the end of June was nearly a million square miles below average for this time of year, compared with data from 1981 to 2010, according to a recent NOAA report. That’s almost four times the size of Texas.

In California, high pressure brought hot conditions to the mountains, deserts and interior valleys over the first half of this week. Significant cooling was expected Thursday, but temperatures are expected to heat up again next week, forecasters say.

A haze of unhealthful air hung over the Great Lakes region in a reminder of the fires that are still raging in Canada and pushing smoke toward the U.S.

June 28, 2023

Large swaths of China and other Asia Pacific countries are being smothered under an oppressive heat wave that has lingered for more than a week, according to media reports. Meanwhile, eastern Canada is in the grips of a broiling heat wave and wildfires that have burned more than 20 million acres and blanketed parts of the Midwest and East Coast in smoke.

The mercury has soared across the U.S. too. This Fourth of July was the hottest on record in Tampa, Fla. — with temperatures hitting 97 degrees, according to the National Weather Service.


Phoenix is seeing slightly above-normal temperatures, even by its typically broiling standards. Forecasts show temperatures will remain above 110 degrees heading into next week, said meteorologist Gabriel Lojero with the local National Weather Service forecast office.

“This is typical for this time of year. We usually get 110 degrees for the region. Average is 107 for this time of the year. We’re observing temperatures slightly above normal,” Lojero said Wednesday.

Extreme heat waves such as the one that hit the Pacific Northwest last year may be 20 times more likely to occur if carbon emissions are not reduced.

Nov. 24, 2022

Deadly heat waves fueled by climate change are becoming more common in parts of the U.S., experts say.

For the first time in several years, El Niño conditions have formed in the tropical Pacific, bringing with them “a likely surge in global temperatures and disruptive weather and climate patterns,” according to the World Meteorological Organization.

“The onset of El Niño will greatly increase the likelihood of breaking temperature records and triggering more extreme heat in many parts of the world and in the ocean,” WMO Secretary-General Petteri Taalas said in a statement.

Along with warmer ocean waters, El Niño can mean increased rainfall in some parts of the world. In the United States, the weather pattern’s influence is typically weaker during the summer and more pronounced in late fall through early spring. Drier conditions are possible for parts of the northern U.S. and Canada — with wetter weather farther south, according to NOAA.


Taalas warned that El Niño’s arrival should be a signal to governments around the globe to prepare for extreme weather. El Niño occurs every two to seven years, and can last anywhere from nine months to a year, according to the WMO.

The agency recently predicted there is a 98% likelihood that at least one of the next five years — and the five-year period as a whole — will be the warmest on record.

“Early warnings and anticipatory action of extreme weather events associated with this major climate phenomenon are vital to save lives and livelihoods,” Taalas said.

Times staff writer Hayley Smith contributed to this report.